Fixed handover not working issue

When vendor qualified networks provider updates the available
networks, transport manager didn't notify the clients handover is
needed. Fixed by updating the available networks after checking
handover is needed or not.

Test: Unit tests + telephony sanity tests
Bug: 124796817

Merged-In: I730b2350e7db3517180431e4b23d7a3fd7a7dd6e
Change-Id: I730b2350e7db3517180431e4b23d7a3fd7a7dd6e
(cherry picked from commit 7e6a8f90)